Final answer:
Three types of natural selection are stabilizing selection, directional selection, and diversifying selection. Stabilizing selection favors the average phenotype, directional selection favors one extreme phenotype, and diversifying selection selects for two or more extreme phenotypes resulting in overlapping distributions.
Step-by-step explanation:
Three types of natural selection are stabilizing selection, directional selection, and diversifying selection.
In stabilizing selection, an average phenotype is favored and the range of variation is narrowed. An example of this is human birth weight, where babies that are very large or very small are less likely to survive.
In directional selection, one extreme phenotype is favored and the distribution shifts towards that extreme. An example of this is the beak size of Galápagos finches observed by the Grants.
In diversifying selection, two or more extreme phenotypes are selected for, resulting in overlapping phenotypes at each end of the distribution. Sexual dimorphism in humans, such as differences in height and body shape between males and females, is an example of this.